The term was transferred by Aristotle from its forensic meaning (procedure in legal accusation) to its logical use as attribution of a subject. The Latin equivalent, prædicamentum, given it by Boethius, aptly suggests its technical significance. The categories or predicaments are the most widely generic classes or groups of predicates applicable to an individual subject--summa genera prædicatorum. Whether Aristotle originally intended them as aspects and divisions of words, of ideas, or of things is a debated question. Nevertheless they lend themselves readily to each of these subjects. They are divisions:

of Ideas in as much as they are the widest generalizations under which all other more restricted ideas may be subsumed;

of words in that they are the oral terms answering to those supreme notions;

of things in the sense that they are aspects which the mind abstracts from the objects falling under experience.

In the first acceptation they belong to logic, where they stand as the ultimate classification of strictly universal ideas; in the second to grammar, where they represent the parts of speech; in the third to ontology, where they are the ultimate classes of real (finite) being. In this latter sense they will be here considered.

Since it is the business of philosophy to reduce the world of real beings--the self included--to its simplest terms or aspects and their orderly relations, the task of discovering and defining the corresponding categories has been attempted by every philosopher of note. The results, however, have been by no means identical. Thus we find the Indian sage, Kanada, the reputed founder of the Vaiseshika philosophy, reducing all things to substance, quality, action, generality particularity, co-inherence, and non-existence, while the Greek (supposed) author of the word philosophy, Pythagoras, discovers twenty ultimate groups, ten of which he calls good and the opposite ten bad. Plato in turn subsumes all things under being, identity, diversity, change. In modern times Descartes and Leibniz arranged seven categories: mind (spirit), matter (body), measure, shape, rest, motion, position, while Kant, basing his division on the varieties of judgment, invented twelve categories or forms under which he makes the intellect(Verstand) judge of all objects of experience. Aristotle's classification of ten categories which was taken up into Scholasticism, and still holds its place in the logic and ontology of Catholic philosophy, is thus set forth in the fourth chapter of the "Organon":

of things in-complex enunciated (i.e. simple predicates), each signifies either substance or quantity or quality or relation or where (place) or when (time) or position or possession or action or passion. But substance is to speak generally as 'man', 'horse'; quantity as 'two' or 'three cubits'; quality as 'white'; relation as 'greater'; where as 'in the Forum'; when as 'yesterday'; position as 'he sits'; possession as 'he is shod '; action as 'he cuts '; passion as 'he burns'.

Of these groups substance, quantity, quality and relation are obviously the principal; the remaining six are reducible to some form of relation, for it should be noted that between some of the categories a real distinction is not required; a virtual, i.e. an objectively founded mental distinction suffices, as, e.g., between action and passion. The object or thing divided into the categories is:

(a) real being i.e. not the mere being expressed by the copulative verb (ens copulæ); nor conceptual being (entia rationis); nor, at least according to many Aristoteleans, being as explicitly actual (ens participium); but substantive or essential being--reality--the object matter of ontology (ens essential non ens existentæ);

(b) being per se, i.e. being having an essential not merely accidental unity--such as an artificial or a random construction (ens per se, non per accidens), or concrete adjectives which include a subject;

(c) complete being, not the abstract differentiæ or the parts of things;

(d) finite being; the Infinite of course transcends all categories. Though the privilege of categorization is thus limited, a method has been devised whereby accommodation may be secured for any (finite) reality whatsoever.

For (a) some beings enter a category directly (in linea recta), as do genera, species, and individuals; (b) others indirectly (a latere), as do specific and individual differentiæ; or (c) others come in by reduction as do the parts of things and things having only an accidental unity (entia per accidens), and even, by analogy, mental fictions (entia rationis). Thus for instance family and hand are reduced to the category of substance; intensity of heat to quality; a point to quantity and so on. It should be noted, however, that being itself as such (ens transcendentale) cannot be confined to a category since it is not a univocal, but only an analogous attribute of the supreme divisions of reality (e.g. substance and accident), and is not therefore a genus as is each category. For the same reason accident is not a genus by itself under which the nine classes mentioned above are subsumed as species. If the foregoing restrictions are taken into account it will be found that the Aristotelean classification answers its purpose--the simplification of the world of finite reality for the sake of investigation--and that on the whole no more workable scheme has thus far been devised.

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